Telephone-transmitter.



PATENTED MAY 1, 1906. W. W. DEAN. TELEPHONE TRANSMITTER. APPLICATION FILED OCT. 27, 1902.

UNITED STATES PATENT OFFICE.

WILLIAM W. DEAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGG SW ITOHBOARD AND SUPPLY CO'IVIPA NY, OF CHICAGO, ILLINOIS,

A CORPORATION OF ILLINOIS..

'TEL'EPHONEQTRANSMITTER:

Patented May 1, 19cc.

Application filed October 2'7, 1902. Serial No. 12 8383.

' large variation of resistance without oomphcation of parts is obtained.

Other ob 'eots are the construction of an instrument that is efficient, durable, and comparatively inexpensive to manufacture.

In the ordinary commercial transmitter the amount of variation of resistance therein'is limited by its necessary features of constructionsuch, for instance, as the depth of the chamber for the carbon granules or other comminuted resistance-varying material and likewise the inertia of the diaphragm and parts operated thereby. If the depth of the chamber is too great and an attempt is made the result is a mufiiin culties by to fully compress the granules between the opposed eiectrodes, the time element entering into the movement is too prolonged and of the sound due to the speech-Waves. T e inertia of the dia phragm and the movable parts also prevent the necessary rapidity of vibration, if such prolonged mgvement thereof is required. It has been attempted tomvercome these diffiroviding the transmitter with a plurality o chambers in association with the dia hragm and by connecting said chambers an the diaphragm in series, whereby the amount of variation isymultiplied as many. times as there are chambers. This construction, however, is unsatisfactory and imfpractical. The multiplicity of chambers necessarily requires-that eachbe small, whereby the heat generated by the assing current cannot be readily dissipate and lnjury to the transmission results. Again, in such devices there is no opportunity for the circue I lation of the granules betwem the 'chamber's,

and hence no convenient on satisfactory method of filling the same,it being almost an impossibility to procure uniform results in this respect in the manufacture of the-device in large numbersl 1 I My invention seeks to provide an instrureadil ment that will accomplish the results sought in a simple and "effective manner, that will not become; overheated in use, thatwill permit a free circulation -of the granular'material, that will allowa free vibration-of the diaphragm, and ,in'which the carbon button or chamber will be disposed in ;the most effective position with reference to the diaphra 'm and in which the chamber may be and expeditiously filled with the gran ar material and with the exact quantity desired for each transmitter, ,Whereby .uniform results in the manufacture of the instrument in large numbers is secured.

'ToQthe accomplishment of these objects and'such others as may hereinafter a pear, my invention. com rises the parts an combinations of parts hereinafter described, and particularly pointed. out in the appended claims, reference being had to the accompanying drawings, forming a part thereof, in which the same reference characters designate like parts throughout the 'severa'l views, and in which Figure 1 is a sectional elevation 01' the de-' vice. Fig. 2 is aview of the parts separated.

Fig. 3 is a rear view of the transmitter. Fig.

4 is a view of a modificationj and Fi 5 .is a.

face view of the rear electrodes and t enrichdia hragm.

he casing of the instrument comprises a metallic. front late 2, circular in form and havinga'centra aperture in which is screwed the usual mouthpiece 3, and which plate is carried by metal disk, preferably aluminium, is provided at its edges with a rubber band 6 and is pressed against a suitable ledge on the rear ofthe front plate 2' by means of the spri -fingers an preferably secured to the me .tallic sol d back or cup '4, the latter part '7 which areprovided with felt :or rub er pads 8 upon. their ends, one of the saidsprings bearing upon the diaphragm toward itscen- 'ter to dampen its iubration and the other bearing upon the band 6; The central portion 5 of the diaphragm is deflected or displaced toward the front to form a chamber 9, in which the carbon granules or other comminuted material forming the resistance-' var; nediurr is adapted'to be carried \Vhile I show this chamber formed integrally with the sound-receiving diaphragm and while it is shown depressed out of the plane thereof, my invention contemplates in some of its aspects any method of forming or carrying said chamber. In the bottom of this depression a brass or other metallic disk is located and is secured therein by a stud or stem 11, passing through an aperture in the bottom of said depression, and a nut 12 is threaded upon sald projection outside the diaphragm. A mica disk 13, forming a supplemental diaphragm, is secured at its periphery at theedge of said chamber by means 0 the metallic ring 14 and a plurality of rivets 15. This disk or diaphragm serves to close said chamber to confine the granules therein. Other suitable material than mica may be employed, and other means for securing it to the edge of the chamber 9 may be employed.

The outer electrode 16 of the instrument,

v preferably of brass, is provided with a cylindrical shank 17, extending through a central aperture in said mica dlsk 13 and thence through the metallic clamping member 18 and its rearwardly-extending sleeve 19, the latter fittin closely over the shank 17 of' the said electrode. The sleeve 19 extends through an aperture in a metallic block or support 20, which is secured in anydesired way, preferably by upsetting its inner end at one or more points, as at 21, in a bridge-piece 22. This bridge 1s a metal bar secured at its ends in suitable notches in the back of the front piece 2 by means of suitable screws 23.

In the depression formed in the front face of the electrode 16 a cup 24,01 insulating material, preferably araifin paper, is located and is secured in p ace by means of abrass or other metallic disk 25, fitting closely Within the cup and having a stem 26 passing rearwardly through an aperture in the bottom of said cup. and thence throu h an insulatingsleeve 27, placed within the ore of the shank 17 of said electrode 16. This disk 25 constitutes the inner electrode of the instrurnent. A mica or other insulating-washer 28 is placed over said stem 26 and in the rear of said shank 17 and the sleeve 19. The washer portion of a terminalclip 29 is laced outside. the insulating-washer 28, an a nut 30 is then threaded upon said stem 26, which upon being tightened serves to clamp the said electrodes strument before the set-screw 31 is tightened.

The vibration of the diaphragm causes the together andto the mica disk. These electrodes and the mica disk are shown in face view in Fig. 5. The parts thus clamped to ether may be adjusted in position in the l ilock 20 and secured therein by means of a suitable set-screw 31. This adjustment 'is readily accomplished bytalking into the inshank 19 to assume the best normal position, when the screw 31 maybe set up to secure the said shank rigidly.

The two electrodes 16 and 25 are thus carried by the disk 13, the outer being of ring form and the inner of a simple diskform, These are preferably goldplated, though it will be apparent that other contact-surfaces may be rovidedv for the same. chamber 9 between the said electrodes and the late 10 and preferably fills the chamber, as .s own, nearl on a line with the uppermost point of t e outer electrode 16. The cup 24 does not touch the disk 10, and hence does not dampen its, vibration. of the cup should be at a distance from the face of the disk 10 a little greater than the thickness of the. carbon granules. .If the grains of carbon are .008 mob in diameter, the ed e of the cup should be about .01 inch from t e disk 10. This arrangement results in permittin the carbon in the chamber to circulate an to pass through the said space from one portion of the chamber to the other,

-wheregf when it is desired to fill the chamber it-is o y necessary to roughly place therein a measured quantity of the granules and to close the chamber. As soon, then, as the in- The granular material is placed in the The edge,

strument is used the carbon will find its proper location, and the instrument will be 1n working condition. Also if in the use of the instrument it is turned through an an le,

so that the portion of the chamber be ore carried in the insulating-block 35, suitably mounted upon and secured to the bridge -22. A circuit-conductor is inserted in the aperture in the post 34 and the set-screw 36 tightened to electrically and mechanically connect the same. The other side=of the circuit is com lered through the arm supporting the bee 4, though a separate'conductor could be employed, if desired. The insulating-cup 24 divides the material in chamber 9, into two portions, so that the current is practically confined thereto and which are in series in the current-path, whereby twice the variation in resistance is secured than if the current traversed the anules but once. This is secured, too, wit out dampening the action of the diaphragm and with the carbon at the most sensitive-and most uniformly vibrated part of the diaphragm. The heat-dissipatin power of the chamber is not decrease over that of the ordinary t' e, and

the granules have free circulation wit all its attending advantages.

The location. ofthe chamber in the diabe departed from, though those shown and described are considered preferable. The inside of the cup is preferably covered with a coat of lacquer or'varnish to insulate the carbon from the walls of the cup.

As shown in Fi 4, the plate 10 may be wholly insulated om'the diaphragm 5, as by the ,mica or other insulating-washers 37, placed u on the threaded pin 11 upon either side of the diaphragm, the opening through the latter being enlarged to prevent contact with the said pin 11. On account of the varnish or lacquer the periphery of plate 10 does not make electrical contact with the diaphra m,

While I have described one form of my irivention, I do notiwish in all respects to be confined thereto,- as it is obvious that various changes and alterations may be made therein and still not depart from its scope and principle.

I claim- 1. In a telephone-transmitter, the combination with a sound-receiving diaphragm, of a single flat shallow chamber containing comminuted conducting material and in which the said material may pass from one part to another, a positive, ne ative and an intermediate electrode in sai chamber, and means to divide the current-path through the material in said chamber into several parts, the arrangement of said electrodes being such as to the said material may passfr'rom 'one part to cause the current to traverse said parts in series, substantially as described. r 2. In a telephone transmitter, the combination with a sound-receiving diaphragm, .of a single flat shallow chamber containing 1 comminuted conducting material and in which the said material may pass .from one part to another, electrodes in said chamber, and means to divide the cur-rent path through the material in said chamber into several parts and to cause the current to traverse said in series, substantially as described. a

3. In, a telephone-transmitter, the" combination with a sound-receiving diaphragm, of a single fiat shallow chamber containing comminuted conducting material and in which parts another, electrodes in said chamber, and means to dividethe current-path through the mate' rial insaid chamber into two parts and to a chamber containing commlnuted conduct-' material, a conducting member on one si e of the chamber and two electrodes on the other, and means to cause the current to pass across the chamber between said electrodes and member in series while at the same time T permitting theematerial to pass fromone part of the chamber to another, substantially as described. v

6. In a telephone-transmitter, the combination with a sound-receiving dia hragm, of a chamber containing comm'inute conducting material, a conductingmember on one side a of the chamber actuated by the dia hragm, and a pair of electrodes on the ot er and o posite side of' said chamber and forming t e terminals of the electric circuit, said electrodes being insulated from each other and means to cause the current to ass from one electrode to the said plate and to the other electrode in series, the said material being permitted to circulate from'one cm the plate gpart to another of the chamber, substantially" as described.

7. In a telephone-transmitter, the. combination with a sound-receiving diaphragm, of v a chamber containing-comminuted conduct-' ing material, *a conductin ,-plate on one side of said chamber, a pair 0 electrodesion the other, an insulating-partition projecting into the said chamber to divide itinto two parts corresponding to said electrodes to cause the .l le'O current to pass in series through theitwo parts of the chamber, said partition at'rthe'.

same time permittin the movement of the comminuted materia from. one pail of the.

chamber to another, substantially as described.

8. In a telephone-transmitter, the combi nation witha sound-receiving diaphra m having a forwardly-deflectedportion,o a

chamber containing comminuted conductin material, a front conducting-plate locate with nusaid chamber and within the for- War dlyedeflected portion of the diaphragm, 7

two electrodes opplosingsaid plate and-ldbated-upon the ot er slde of the chamber,- comminuted conducting material carriedin said chamberbetween said plate and the elec-.

trodes," said electrodes being insulated from ing material, a conducting-plate on one side of said chamber and located within said deflected portion, two electrodes on the other side ofsaidchamber o posed 'to the conducting-plate, the outer e ectrode being of ring form and the inner electrode of disk form fitting within the inner periphery of the ring, said electrodes being insulated from each other, a forwardly-extending insulatinga'rtition projecting nearly across the cham er, and a rigid support for said electrodes, substantially as described.

10. In a telephone-transmitter, the combination with a shallow chamber containing comminuted conducting material, of an electrode on one side of the chamber, a plurality of electrodes on the opposite side of the chamber, an insulating-partition be ,ween said latter electrodes promoting into the chamber toward the first-mentioned electrode but terminating short of the same, granular carbon in said chamber between said opposed electrodes, said material being adapted to pass from one art of the chamber to the other between sai first electrode and the edge of said partition, substantially as described.

11. In a telephone-transmitter, the combination with a shallow chamber containing comminuted conducting material, of an electrode on one side of the chamber, a pair of electrodes on the other side of the chamber, one of said latter electrodes having a de ression in its inner face, an insulating-cup a apted to fit within said depression with 1ts edges projecting forwardly into the chamber and nearly across the same toward the opposite electrode, the other electrode of said pair fitting within said cup, whereby said electrodes are insulated from each other and the chamber is -divided into two parts, substantially as described,

12. In a telephone-transmitter, the combination with a shallow chamber containing comininuted conducting material, of an electrode on one side ofthe chamber, a pair of electrodes on the opposite side of the chamber, one of said latter electrodes having a rearwardly-extending sleeve, an insulatingcup, the other of said pair of electrodes fitting within said cup and having a stem passing through said sleeve but insulated therefrom,

the e ges of said cup projecting forwardly into the chamber and toward the first-named electrode to form an'insulating-partitiori in the chamber and said cup serving toinsulate the two electrodes of the pair, said sleeve and stem forming the terminals of the electrodes and being secured together to clamp said pair of electrodes and the cup together, substantially as described.

13. In a telephone-transmitter, the combination with a shallow chamber containing comminuted conducting material, of an electrode on one side of the chamber, a pair of.

electrodes on the opposite side of the chamber, one of said latter electrodes havin a sleeve extending'from its outer face an a nation with a -main sound-receiving dia'' phragm, of a single chamber suitably associ ated therewith and containin a number of compartments, a small, supplemental flexible diaphragm for closing one side of said chamber, comminuted conducting material in said compartments, ada ted to ass from one compartment to anot er, an e ectrode in each of said compartments, and means to cause the current to pass through said comminuted material in said compartments in series between said electrodes, substantially as described. l

15. In a teiephone-transmitter the combi- J.

.with and containing two compartments, a

supplemental diaphragm of insulating material adapted to close both compartments, and partaking of the movement of said firstmentioned diaphragm, comminuted conducting material in said compartments, an electrode ineach of said compartments on the same side of said chamber, and means to cause the current to pass through the conducting material in sa1d compartments in series between said electrodes, substantiallyas 5 described.

16. In a telephonetransmitter, the combi nation with a main sound-receiving diaphragm," of a chamber containing comminuted conducting material, an insulatin supplemental diaphragm for closing sai chamber, two electrodes on the side of said chamber closed by said supplemental diaphragm and vibratory therewith, and means whereby the current fromone "electrode to the other must twice pass transversely across the chamber, substantially as described;

17. In a telephone-transmitter, the combination with a sound-receiving diaphragm, of a chamber containing commmuted conducting material, a suitable partition within said chamber projecting into said material, two electrodesfor said chamber, one upon either side of said partition, a su plemental diaphragm associated with sai electrodes and closing said chamber, and means whereby current in passing from one electrode .to the other must crossthe chamber in two directions, substantially as described. I 18. In a telephone-transmitter, the combination with a sound-receiving diaphragm, of

a chamber-containing comminuted conducting material associated with said diaphragm, a supplemental diaphragm of insulating material constituting one wall of said chamber, a non-conducting partition in said chamber dividing the comminuted conducting material into a plurality of compartments, two

electrodes in said chamber, and means forcausmg current to pass from one electrode to" the other through the material of all compartments in series, substantially as described. 4

19. In a telephone-transmitter, the combination with a main diaphragm, of-a chamber associated therewith, comminuted conducting material within said chamber, a flexible supplemental diaphragm of insulating mate- I rial for closing one side of saidchamber, a

pair of electrodes on the side of said chamber closed by said supplemental diaphragm, and a suitable insulating partition separating said electrodes and projecting into said material, while permitting said material to pass from one side thereof to the other, the current beln adapted to travel around said partition an through the comminuted material upon either side thereof in series, substantially as described.

' 20. In a telephone-transmitter, the combination with a main diaphragm, of a chamber associated therewith, comminuted conduct-- ing material within said chamber, a flexible supplemental diaphra for closing one side of said chamber, a pair of electrodes on the side of said chamber closed b said supplemental diaphragm, anelectro e upon the opposite side of said chamber, and a suitable introdes and project ng into sai material,

'while ermitting said material to pass from.

one si e thereof to the other, thecurrent be: ing adapted to travel. around sa d partition and through the comminuted material upon either side thereof in series, substantially .as

described.

' '21. In a telephone-transmitter, the combination with a main sound-receiving d1aphragm, of a chamber associated therewith, a rigid support for oneside of saidcha nber, a flexlble 'suplplemental diaphragm of msulating materia interposed between sa d support 'and'said main diaphragm and constituting one wall of said chamber, comminuted .con-

4 ducting material within'said chamber, a ar tition in said chamber suitably secure to one side thereof and projecting into said ma-' wall of said chamber, a pair of. electrodes within said chamber mounted on said insulating-diaphragm, and a partition extending from one side of said chamber into said comminuted conducting material butstopping short of the opposite side thereof, whereby the current is obliged to traverse the divided portions of said comminuted conducting material in series, substantially as described.

Signed b me at Chicago, count of Cook, State of 11 inois, this '23d day o October,

'WILLIAM W. DEAN. Witnesses:

ROBERT LEwIs AMEs, GAZELLE BEDER.

'sulating-partition separating said air of elec- I 

